Pixel Circuit Compensation for LED Light Emission Stability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing pixel circuits face instability in light emission and safety concerns due to threshold voltage drift in driving transistors and inadequate initialization of LED anodes, leading to unstable LED lighting and potential circuit damage.
Innovation Solution
A pixel circuit design incorporating a compensation unit, driving unit, light emitting unit, capacitor, and initialization unit, where the compensation unit sets a voltage on a node with a compensation voltage, the capacitor holds this voltage, and the driving unit generates a driving current based on the threshold voltage of the driving transistor, ensuring stable light emission and improved safety by avoiding simultaneous initialization of the node and LED.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single transistor is used between power supply and data signal for threshold compensation, then the circuit complexity is reduced, but the light emission stability deteriorates due to power supply leakage current
Solution Approach 1:
The patent divides the compensation path into two separate transistors (first compensation transistor and second compensation transistor) instead of using a single transistor. This segmentation isolates the compensation function from the power supply leakage current path, allowing stable threshold voltage compensation while preventing power supply noise and leakage from affecting the data signal and light emission stability.
2Device complexity
If both gate electrode of driving transistor and anode of LED are initialized simultaneously, then the initialization process is simplified, but circuit safety deteriorates due to instantaneous current
Solution Approach 1:
The patent segments the initialization process into two distinct stages: first initializing the gate electrode of the driving transistor, then subsequently initializing the anode of the LED. This temporal segmentation prevents simultaneous initialization that would cause instantaneous current, while maintaining a simple overall initialization process through sequential control.
Solution Approach 2:
The patent applies preliminary action by initializing the gate electrode of the driving transistor before initializing the anode of the LED. This preliminary initialization ensures that the driving transistor is properly prepared and in a safe state before the LED anode is initialized, preventing harmful instantaneous current while completing the full initialization sequence.
Data Source
AI summary
A pixel circuit, a driving method and a display device having the pixel circuit are disclosed, wherein the pixel circuit comprises a compensation unit, a driving unit, a light emitting unit, a capacitor, an initialization unit and an external power supply and the driving method comprises a first initialization stage, a second initialization stage, a data writing stage and a light emitting stage.